/*
 * 
 * File: OSXAdapter.java
 * 
 * Abstract: Hooks existing preferences/about/quit functionality from an existing Java app into
 * handlers for the Mac OS X application menu. Uses a Proxy object to dynamically implement the
 * com.apple.eawt.ApplicationListener interface and register it with the com.apple.eawt.Application
 * object. This allows the complete project to be both built and run on any platform without any
 * stubs or placeholders. Useful for developers looking to implement Mac OS X features while
 * supporting multiple platforms with minimal impact.
 * 
 * Version: 2.0
 * 
 * Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc. ("Apple") in
 * consideration of your agreement to the following terms, and your use, installation, modification
 * or redistribution of this Apple software constitutes acceptance of these terms. If you do not
 * agree with these terms, please do not use, install, modify or redistribute this Apple software.
 * 
 * In consideration of your agreement to abide by the following terms, and subject to these terms,
 * Apple grants you a personal, non-exclusive license, under Apple's copyrights in this original
 * Apple software (the "Apple Software"), to use, reproduce, modify and redistribute the Apple
 * Software, with or without modifications, in source and/or binary forms; provided that if you
 * redistribute the Apple Software in its entirety and without modifications, you must retain this
 * notice and the following text and disclaimers in all such redistributions of the Apple Software.
 * Neither the name, trademarks, service marks or logos of Apple Inc. may be used to endorse or
 * promote products derived from the Apple Software without specific prior written permission from
 * Apple. Except as expressly stated in this notice, no other rights or licenses, express or
 * implied, are granted by Apple herein, including but not limited to any patent rights that may be
 * infringed by your derivative works or by other works in which the Apple Software may be
 * incorporated.
 * 
 * The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO WARRANTIES, EXPRESS
 * OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT,
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
 * OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
 * 
 * IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
 * MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY
 * OF CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright © 2003-2007 Apple, Inc., All Rights Reserved
 * 
 */

package org.openpnp.gui.support;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class OSXAdapter implements InvocationHandler {

    protected Object targetObject;
    protected Method targetMethod;
    protected String proxySignature;

    static Object macOSXApplication;

    // Pass this method an Object and Method equipped to perform application shutdown logic
    // The method passed should return a boolean stating whether or not the quit should occur
    public static void setQuitHandler(Object target, Method quitHandler) throws Exception {
        setHandler(new OSXAdapter("handleQuit", target, quitHandler));
    }

    // Pass this method an Object and Method equipped to display application info
    // They will be called when the About menu item is selected from the application menu
    public static void setAboutHandler(Object target, Method aboutHandler) throws Exception {
        boolean enableAboutMenu = (target != null && aboutHandler != null);
        if (enableAboutMenu) {
            setHandler(new OSXAdapter("handleAbout", target, aboutHandler));
        }
        // If we're setting a handler, enable the About menu item by calling
        // com.apple.eawt.Application reflectively
        Method enableAboutMethod = macOSXApplication.getClass()
                .getDeclaredMethod("setEnabledAboutMenu", new Class[] {boolean.class});
        enableAboutMethod.invoke(macOSXApplication,
                new Object[] {Boolean.valueOf(enableAboutMenu)});
    }

    // Pass this method an Object and a Method equipped to display application options
    // They will be called when the Preferences menu item is selected from the application menu
    public static void setPreferencesHandler(Object target, Method prefsHandler) throws Exception {
        boolean enablePrefsMenu = (target != null && prefsHandler != null);
        if (enablePrefsMenu) {
            setHandler(new OSXAdapter("handlePreferences", target, prefsHandler));
        }
        // If we're setting a handler, enable the Preferences menu item by calling
        // com.apple.eawt.Application reflectively
        Method enablePrefsMethod = macOSXApplication.getClass()
                .getDeclaredMethod("setEnabledPreferencesMenu", new Class[] {boolean.class});
        enablePrefsMethod.invoke(macOSXApplication,
                new Object[] {Boolean.valueOf(enablePrefsMenu)});
    }

    // Pass this method an Object and a Method equipped to handle document events from the Finder
    // Documents are registered with the Finder via the CFBundleDocumentTypes dictionary in the
    // application bundle's Info.plist
    public static void setFileHandler(Object target, Method fileHandler) throws Exception {
        setHandler(new OSXAdapter("handleOpenFile", target, fileHandler) {
            // Override OSXAdapter.callTarget to send information on the
            // file to be opened
            public boolean callTarget(Object appleEvent) {
                if (appleEvent != null) {
                    try {
                        Method getFilenameMethod = appleEvent.getClass()
                                .getDeclaredMethod("getFilename", (Class[]) null);
                        String filename =
                                (String) getFilenameMethod.invoke(appleEvent, (Object[]) null);
                        this.targetMethod.invoke(this.targetObject, new Object[] {filename});
                    }
                    catch (Exception ex) {

                    }
                }
                return true;
            }
        });
    }

    // setHandler creates a Proxy object from the passed OSXAdapter and adds it as an
    // ApplicationListener
    public static void setHandler(OSXAdapter adapter) throws Exception {
        try {
            Class applicationClass = Class.forName("com.apple.eawt.Application");
            if (macOSXApplication == null) {
                macOSXApplication = applicationClass.getConstructor((Class[]) null)
                        .newInstance((Object[]) null);
            }
            Class applicationListenerClass = Class.forName("com.apple.eawt.ApplicationListener");
            Method addListenerMethod = applicationClass.getDeclaredMethod("addApplicationListener",
                    new Class[] {applicationListenerClass});
            // Create a proxy object around this handler that can be reflectively added as an Apple
            // ApplicationListener
            Object osxAdapterProxy = Proxy.newProxyInstance(OSXAdapter.class.getClassLoader(),
                    new Class[] {applicationListenerClass}, adapter);
            addListenerMethod.invoke(macOSXApplication, new Object[] {osxAdapterProxy});
        }
        catch (ClassNotFoundException cnfe) {
            System.err.println(
                    "This version of Mac OS X does not support the Apple EAWT.  ApplicationEvent handling has been disabled ("
                            + cnfe + ")");
            throw cnfe;
        }
    }

    // Each OSXAdapter has the name of the EAWT method it intends to listen for (handleAbout, for
    // example),
    // the Object that will ultimately perform the task, and the Method to be called on that Object
    protected OSXAdapter(String proxySignature, Object target, Method handler) {
        this.proxySignature = proxySignature;
        this.targetObject = target;
        this.targetMethod = handler;
    }

    // Override this method to perform any operations on the event
    // that comes with the various callbacks
    // See setFileHandler above for an example
    public boolean callTarget(Object appleEvent)
            throws InvocationTargetException, IllegalAccessException {
        Object result = targetMethod.invoke(targetObject, (Object[]) null);
        if (result == null) {
            return true;
        }
        return Boolean.valueOf(result.toString()).booleanValue();
    }

    // InvocationHandler implementation
    // This is the entry point for our proxy object; it is called every time an ApplicationListener
    // method is invoked
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        if (isCorrectMethod(method, args)) {
            boolean handled = callTarget(args[0]);
            setApplicationEventHandled(args[0], handled);
        }
        // All of the ApplicationListener methods are void; return null regardless of what happens
        return null;
    }

    // Compare the method that was called to the intended method when the OSXAdapter instance was
    // created
    // (e.g. handleAbout, handleQuit, handleOpenFile, etc.)
    protected boolean isCorrectMethod(Method method, Object[] args) {
        return (targetMethod != null && proxySignature.equals(method.getName())
                && args.length == 1);
    }

    // It is important to mark the ApplicationEvent as handled and cancel the default behavior
    // This method checks for a boolean result from the proxy method and sets the event accordingly
    protected void setApplicationEventHandled(Object event, boolean handled) {
        if (event != null) {
            try {
                Method setHandledMethod = event.getClass().getDeclaredMethod("setHandled",
                        new Class[] {boolean.class});
                // If the target method returns a boolean, use that as a hint
                setHandledMethod.invoke(event, new Object[] {Boolean.valueOf(handled)});
            }
            catch (Exception ex) {
                System.err.println("OSXAdapter was unable to handle an ApplicationEvent: " + event);
                ex.printStackTrace();
            }
        }
    }
}
